Thyroid Flashcards
where does the thyroid sit
C5-T1
in the anterior portion of the neck
what is its relations
ant: pre-tracheal muscles + skin
post: four parathyroid glands, one at each upper pole and one at each lower pole of each lobe. behind the middle portion is the isthmus
sup: larynx
what is it lined with
cuboidal epithelium
what does the thyroid follicles produce
thyroglobulin
what does the central cavity store and secrete
colloid
thick sticky protein which contains thyroglobulin attached to iodine, which helps in the hormone production
what surrounds the thyroid follicles
parafollicles which secrete calcitonin
what do thyroid follicles do
manufacture, store and secrete hormones
what does thyroglobulin contain
tyrosine which binds with iodine to produce T4 and T3 in iodine trapping
T4
two tyrosine moles and 4 iodine [major hormone secreted]
T3
two tyrosine and three iodine
formed mainly in the conversion at target tissues
what does the thyroid wrap around
the thyroid cartilage
what is the blood supply
highly vascular
supplied by the R + L superior thyroid arteries which are branches of the external carotid arteries
R+ L inferior thyroid arteries are branches of the subclavian
isthmus -> thyroid ima artery os a branch from the external carotid
venous: via a network at the surface of the gland: thyroid veins which are drawn into the internal jugular vein
is it a rare cancer
yes
aetiology
areas of nuclear disaster
previous RT
autoimmune conditions
genetic factors
what are the five pathology types
papillary
follicular
anaplastic
medullary
malignant lymphoma
what are the differentiated types
papillary and follicular
describe papillary
common, slow growing, finger like projections of stroma
describe follicular
occur in patients with goitre
appears solid, solitary, well circumscribed mass
minimal or widely invasive
what can be tracked with differentiated tumours
hormone production, as they produce thyroid hormones
what tumours are undifferentiated
anaplastic and medullary
describe anaplastic
giant or spindle cell
rapid growth and radioresistant
describe medullary
arises from para-follicular cells
slow growing
can contain calcium [if not present it indicates a more aggressive tumour]
describe malignant lymphoma
non hodgkins
varies from high to low grade
what is a T1a
solitary <1cm